Climate change, beetle may doom rugged pine

SAWTOOTH RIDGE, Okanogan County — The bug lady scoots through stick-straight lodgepole and ponderosa, and marches uphill toward the gnarled trunk of a troubled species: the whitebark pine.

The ghostly conifers found on chilly, wind-swept peaks like this may well be among the earliest victims of a warming climate. Even in the Northwest, rising temperatures at higher elevations have brought hundreds of thousands of whitebark pines in contact with a deadly predator — the mountain pine beetle — that is helping drive this odd tree toward extinction.

Connie Mehmel, with the Okanogan-Wenatchee National Forest, is one of a handful of entomologists struggling to track the beetles' destructive path.

Mountain pine beetles are probably best-known here as the trunk-girdling devils that have reddened and deadened millions of acres of lodgepole, exposing the Northwest to a greater potential for cataclysmic wildfires. But the evolutionary history of lodgepole pine and beetles is so intertwined that those forests in many places are expected to grow back.

Whitebark pines may not.

"What concerns me and a lot of people in my line of work is we are seeing beetles being more active in areas where we didn't use to see them — particularly in higher-elevation areas," Mehmel says. "We have thousands of acres of whitebark pine that are being attacked by mountain pine beetles, more than we've seen in quite a long time."
Much attention has been paid to the way pine beetles have gnawed through whitebark forests in the Northern Rockies, particularly in Yellowstone National Park, where the trees' seed cones provide important food for grizzly bears.

But the beetles also are whittling away at whitebark in Northwest areas once thought safe from bugs.

When it comes to the number of acres or trees killed by beetles and an invasive fungus called white pine blister rust, hard data typically requires aerial surveys and is frustratingly inexact. Researchers instead focus on trend lines.

And in the Northwest, they all point in one direction. A study in the mid-2000s showed whitebark trees had declined by 41 percent in the Western Cascades. Tree declines throughout Washington and Oregon hovered around 35 percent. In the coastal range and the Olympics, blister rust infection ranged from 4 to 49 percent. Nearly 80 percent of the whitebark in Mount Rainier National Park are infected. Whitebark deaths in North Cascades National Park doubled in the last five years.


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